Originally Posted by Firegazer:
“I think it's two episodes on Christmas Day. One earlier, and one later.”
We don't know what's happening on Christmas Day yet. Won't know until last November/early December. Airing as two episodes or as an hour, either way it will still count as two episodes.
If there's an extra episode on Christmas Eve and two episodes on Christmas Day and New Year's Day, but no extra episode on New Year's Eve, the 5000th episode should be Monday 19th January, which works out well as that's exactly a month before the anniversary. I think using the 5000th episode to kick off the final month of the Lucy storyline would be a great idea, would be a good time to really start all the 30th promotion as well.
(I went off Radio Times saying that the episode on 31st October is the 4952nd btw.)